Tech Review: Shimano Ultegra Di2

Shimano’s Di2 electronic shifting platform became an instant success when they launched their Dura Ace version in 2009. Just a couple of years on and the technology has filtered down and the Ultegra Di2 groupset is a reality. This groupset brings electronic shifting to a wider audience at a far more affordable price. We have now had chance to thoroughly test the new Ultegra Di2 and are impressed with the results.

While it might be Shimano’s second in command groupset, the reality is that it’s hard to tell the two apart in the way they operate – Ultegra Di2 is that good. Shifting is precise and smooth with little in the way of noise, and what’s noticeable is just how much quieter the Ultegra Di2 shifts compared to a regular mechanical shifter. Being trickle down technology this groupset also takes much of its styling from it’s more expensive peer, especially the electronic parts, namely the lever shifters and the front and rear mechs. What’s also impressive is how maintenance-free the set up is. In fact after initial set up we haven’t had to touch a single thing. Here’s a run down on of the parts:

Dual Control Levers (313g)
The dual control levers are the same shape as their Dura-Ace big brother and the contoured hoods are something your hands feel naturally at home on. They feel more comfortable than the previous mechanical incarnation, which was by no means bad. Smaller handed riders will also appreciate the lever position can be adjusted under the hood for a shorter reach.

When it comes to shifting the action feels as light and easy as the more expensive Dura Ace model. It’s simply a case of moving the levers a millimetre or so for smooth up and downshifts. If you’re new to electronic shifting it feels completely natural within a couple of rides but feels almost too light to begin with.

When it comes to braking the levers are ergonomically shaped and your hands sit naturally into the lever whether you’re on the hoods or the hooks. To be honest you notice very little, which is a good thing because this shows just how comfy and easy they are to use.

Front Mech (162g)
The front mech is impressive with quick precise shifting that feels extremely positive. What’s extremely impressive is that even under full power when climbing we have never managed to drop a chain. What’s also neat and helps to keep things quiet is the fact that as you move up and down the cassette the front mech automatically adjusts to avoid any chain rubbing. While it’s not advisable this still wasn’t an issue in the extremes of big front ring and big rear sprocket, or similarly in small and small.

Rear Mech (270g)
As with the front mech the rear takes much of its styling and shape from its more expensive peer. Gear changes are smooth, quick and far more precise than any mechanical system. Changing multiple gears, however, is slower than its cable operated equivalent because you can’t dump several gears with a single swing of the lever. Instead you need to tap the button several times. Even under full power out of the saddle there were no arguments. The rear mech will work with chainsets with 52/39T or 53/39T, as well as a compact chainset, and can cope with up to 28T on the rear cassette. There’s also a crash saver function that will disconnect the motor in the event of an accident.

Battery (71g)
One of the most frequently asked questions when talking about the Di2 platform is about battery life and charging. The battery Shimano uses here is the same as on their top end on Dura Ace groupset and as so offers around 1 000 kilometres per charge, but naturally that depends on how frequently you change gear. There’s ample warning with a battery indicator light so there’s no excuse for running out of juice on the road. If you do run out on the road the front mech will stop functioning first, which allows the full range of rear gears to get you home. Recharge time is around 90 minutes and Shimano guarantee at least 500 charges per battery.

Di2 Cables And Controls
The Ultegra electronic cables are different to the Dura Ace version using what Shimano call Etube cables. These use two core wires compared to Dura Ace’s four and run with smaller connectors, therefore the two systems are not interchangeable. These cables are also smaller in diameter at 5.1 mm (Dura Aca are 8.8mm) so manufactures running bikes with the groupset can use smaller cable holes in the frame. Naturally you don’t have to run the cables internally and many without internal cables will have no choice. All cables are waterproof from the moment they’re connected and we’ve had no issues during testing.

The control box is small rectangular box that sits at the front end so you can see what’s happening on the fly. Essentially this tells you how much charge is left in the battery

Weight
Weight isn’t a big issue with the Ultegra Di2 groupset with small increases in weight across the board compared to Dura Ace. The complete Ultegra Di2 system weighs 2,482g compared to 2,21 9g for it’s more expensive sibling. For example the Ultegra levers weigh 31 3g (58g more than Dura Ace), the front mech is 1 62g (38g more), the rear mech is 270g (45g more) and the batteries are the same at 71 g. Weight differences are so small most will struggle to justify the extra expense for Dura Ace.

TT Compatibility
The only downer is that there isn’t a TT setup to use with the Ultegra Di2 system at present. We hear something is on the way but at the moment it can’t be used as TT up and is not compatible with the current Dura Ace Di2 TT shifters.

Conclusion
As we mentioned when looking through the individual parts the overall shifting is sharp, smooth and precise and best of all requires no maintenance once set up. Whether it’s speeding up and down the rear cassette or swapping from big to small ring there are no issues, regardless of how much power you’re putting through the cranks. The big difference, apart from the small weight savings, refinements and titanium parts you’d expect with Dura Ace, are the motors used in the front and rear mechs. These are off the shelve motors rather than Shimano’s purpose built and designed motors found in the Dura Ace groupset but they work so well it’s hard to notice any difference. We’re sure weight weenies and those with deep pockets will always buy Dura Ace, but for the rest of us mortals the Ultegra offers a real alternative that perfroms so well it’s hard to justify spending the extra.